<!DOCTYPE html>  
<html lang="en">  
<head>  
  <meta charset="UTF-8">  
  <meta name="viewport" content="width=device-width, initial-scale=1.0">  
  <title>Popup</title>  
  <!-- 引入构建后的CSS -->  
  <link rel="stylesheet" href="index.css">  
</head>  
<body>  
  <div id="app"></div>  
  <!-- 引入构建后的JavaScript -->  
  <script type="module" src="main.js"></script>  
</body>  
</html>